The dorsal component of the scapholunate interosseous ligament is the primary stabiliser, being the thickest and strongest of the three SLIL components. Its isolated partial tear produces occult dorsal wrist pain with preserved radiographic alignment (dynamic instability). Its complete tear combined with the other components produces the full SLIL dissociation pattern.
| Origin | Dorsal scaphoid |
|---|---|
| Insertion | Dorsal lunate |
| Actions | The strongest component of the SLIL — primary restraint against scapholunate dissociation and rotatory subluxation of the scaphoid |
|---|
The Watson scaphoid shift test stresses the dorsal SLIL — the examiner places thumb pressure on the scaphoid tuberosity while ulnar to radially deviating the wrist; the proximal scaphoid subluxes dorsally when the dorsal SL ligament is insufficient. Wrist arthroscopy grades SLIL tears by the Geissler classification from Grade I (haemorrhage) to Grade IV (gross instability).
Isolated dorsal scapholunate ligament partial injury producing dynamic instability with preserved radiographic alignment managed with arthroscopic assessment and thermal shrinkage or open repair.
